in my last house i faced that decision. i chose stick built with closed cell foam(i wouldnt use Icynene in any case). i saved about 6-7k over sips. i regret it.

vhehn, thanks for the reply. Could you elaborate on why you regret not using SIPs? Also why wouldn't you use Icynene?

yokatta,

Do you mind telling us what part of the country you live in?

What I understand is that closed cell foam has almost twice the R value per inch of icynene.

I'm not badmouthing SIP construction - but it needs to be considered as a complete system with people who have experience with it. It changes the way everything else is done. Just for example, finish carpentry becomes more difficult.

I too would like to know why Vhehn regretted his choice of stick and foam. It would be my choice - perhaps because it's more familiar to me.

i regret it because my prior house was built with sips and i got to see the how good they are. when i speced this house the sips had gone up in price a lot so i thought i could save some money.
i dont like Icynene because through somewhat overhyped marketing they have been able to price Icynene very close to poly foam but it is only half as good as poly.

I prefer SPF to Icynene, it just seems like a better product.

I have no experience with SIPs (can't get motivated by it).

I'd be more concerned with creating a tight well thought out envelope than R-value.

if you are considering SIPs at all you should consider steel sips..............
We had used OSB , but have switched to steel for the resons listed:
Although any SIP construction will save 50 Â 60% in energy costs, are 3 times stronger than frame, and are more environmentally friendly. Steel is a better choice for the following reasons

Advantages of Steel SIPs vs.OSB

ï¶ Steel will not warp, swell, twist, rot
ï¶ Rain during construction do not affect materials in any way
ï¶ No cranes needed for installation a steel SIPs are lighter than OSB
ï¶ The underside of the roof panel automatically forms an attractive finished soffit overhang or exterior porch ceiling.
ï¶ Joints are a T&G friction fit they do not require splines, mastic or fasteners greatly speeding installation time
ï¶ Steel is more stable during manufacturing and panels are held to 1/16' tolerance
ï¶ OSB is limited to 24ft. in length ÂSteel SIPs are available up to 53ft. in length, eliminating butt joints
ï¶ Steel panels are manufactured on a continuous line making them available in square pre-cut lengths in ¼ ' increments, but only charged to the nearest ½ ft., OSB often rounds up to the nearest 2 ft. increment  making you pay for waste that gets thrown away
ï¶ Higher ' R  Value' denser foam provides a 4.25 R- value per inch of foam
ï¶ No Termites  Impervious to termites and carpenter ants , foam core is borate treated
ï¶ No foam grooving is required for window and door openings, after cutouts are made, openings are simply 'picture framed' with 18.ga. steel channels
ï¶ The steel skin is the 'vapor barrier' on walls no additional covering is required before siding is applied
ï¶ Eave overhangs can be 4 feet with no additional support
ï¶ Sound Control  utilizing a 1-1/2' steel furring strip creates a dead air space for improved STC ratings.
ï¶ Wiring  utilizing that same air space, wiring is much easier than fishing wire thru OSB and any future retrofit wiring is easier.
ï¶ Will not support mold growth  painted galvalume steel skins are UDSA approved
ï¶ Indoor air quality is better due to the tighter and cleaner construction material of the interior
ï¶ Any steel building is safer from lightning strikes
ï¶ 'Monocoque construction' All connections and attachments are with screws having greater pullout strength than nailing
ï¶ For economy or insulated utility buildings, steel SIPs have been left exposed as the finished siding and roofing.
ï¶ Zurich Ins. In partnership with the Steel Framing Alliance offer reduced builders risk insurance premiums
ï¶ In Florida and other hurricane prone regions Steel SIPs are 30% less to insure that block/truss and 53% less to insure than wood frame construction

Here is a link that might be useful: steel SIPs

From an information standpoint, I visited the Icynene website. Not very user (homeowner) friendly site.

Trying to see what dealers were around, they want your whole life history, and your first-borne child; not just a simple zip-code.

A real turn-off for me.

V

Thanks for all the replys. Jake, I am building in Northern Utah where the temps range from -15 to 98°F. However the average winter temp is around 25°F and summer around 90°. I think the SIP is probably a better product, but will an R value of 42 vs 20 in my walls save that much? My bid for Icynene is around $1.70/sq ft and for SIP is $5/sq ft with a 6" wall.

This is one product I was looking at that has a vapor barrier already installed. http://www.raycore.com
How much more is the steel SIP. I've never seen this product.

I used open cell in all of my walls and closed cell in my roof (rafters). Both were non-Icynene products. Open cell was BioBased and the closed cell was DOW. I am very happy with the result. You DO have to make sure the installer knows what they are doing. I had to have mine touched up after the fact since in a lot of places the open cell shrunk a bit while curing leaving gaps next to the studs... spending all that money there should be no air gaps anywhere. They resprayed all the gaps. Also, with the closed cell, cover everything near. As opposed to open cell, the closed cell has fallout that drys on any surface like little sandpaper grit. Every time I have to get up in between my collar ties in the attic I end up with scrapes somewhere on my arms.

But performance wise... I am very happy. In the dead of summer with temps in the 90s outside, my attic is in the 70s.

in your origianl post you said:
I'd still have to Icynene my attic either way..

If you choose SIPS (excellent product btw, its how
I would build) you could have sips panels either
as the ceiling (unconditioned attic,,vented)
or as the roofline (semi conditioned attic,,nonvented)
both are good installs although given the 30% duct loss
that most homes have..unvented is better,
this puts equipment and ducts (when located in attic)
in a semi conditioned space meaning less heat/cold gain
to ducts and longer life of mechanicals due to less excessive temps.

SIPs is a better choice imo and experience because you have less thermal transfer, continous r-value (unlike foam insulation that varys in thickness from rafter bay to rafter bay) and is solid sheeted for addtional structrual strength.

There have been very few foam insulated attics that I have tested in my 10+ years that are actually unvented..and the the installed R-value is actually the number quoted to the homeowner.

Keep in mind OP that sizing of hvac system will less with SIPS than in regular construction.
Best of luck!

Steel sips are available thru www.SipDepot.com and homes vieable at www.southernsips.com

Here is a link that might be useful: steel sips

I think we got it the first time...cmkavala